Verifiable evaporation modeling on the Laurentian Great Lakes

Abstract

Water or energy balance estimates of Great Lakes evaporation require storage change data, not available in simulations or forecasts, and errors in the components of the balances are summed in the residual, giving large estimation errors. Neither these balance estimates nor evaporation models, which use the aerodynamic equation with mass transfer coefficients developed originally in the Lake Hefner studies, can be verified, since independent estimates of evaporation are not available with sufficient accuracy. However, water surface temperatures can be used to verify energy budgets. The mass transfer coefficient research is combined here with lumped concepts of classical energy conservation and a new superposition heat storage model to provide continuous simulation capability of both water surface temperatures and lake evaporation for use in outlooks and forecasts of lake levels. Calibration matches remotely sensed water surface temperatures for those Great Lakes with observations over the past 20 years. Model sensitivities are analyzed and heat and water budgets are compared. _ ß Mollurod • J F M AM J J A $ O N D

Automated calculation of surface energy fluxes with high-frequency lake buoy data

“…3a). When the atmospheric boundary layer was stable, which can be determined by the difference between air and surface water temperatures (Croley, 1989;Derecki, 1981), air temperature calculated at 10 m was marginally higher than that measured at the sensor height. However, when the atmospheric boundary layer was unstable, air temperature at the measurement height was greater than that at 10 m. As expected, the transfer coefficient for sensible heat at the measurement height was consistently higher than that at 10 m (Fig.…”

Evaluating and improving modeled turbulent heat fluxes across the North American Great Lakes

“…The datasets available for 5 validation of ocean dynamical models, for example, include satellite-based surface water temperatures (Reynolds et al, 2007), sea surface height (Lambin et al, 2010), and, when available, in situ measurements of sensible and latent heat fluxes (Edson et al, 1998). Dynamical and thermodynamic models for large lakes are often verified using similar measurements (Chu et al, 2011;Croley, 1989aCroley, , 1989bMoukomla and Blanken, 2017;Xiao et al, 2016;Xue et al, 2016). 10 However the spatiotemporal resolution of in situ measurements for these variables in lakes is comparatively sparse (Gronewold and Stow, 2014), particularly for latent and sensible heat fluxes.…”

“…The Large Lake Thermodynamic Model (Croley, 1989a(Croley, , 1989bCroley et al, 2002;Hunter et al, 2015), LLTM, is a conventional lumped conceptual lake model. It is employed in seasonal operational water supply and water level forecasting by water resource and hydropower 5 management authorities (Gronewold et al, 2011) and is used as a basis for long-term historical monthly average evaporation records (Hunter et al, 2015).…”

Effects of atmospheric stability conditions on heat fluxes from small water surfaces in (semi-)arid regions

“…When the skin (water surface) temperature (T ws ) is higher than air temperature (T a ), the atmospheric boundary layer is unstable and convective. The air and water surface temperature (skin temperature) differences can be used as a measure of atmospheric stability (Derecki 1981, Croley 1989. In an unstable atmospheric boundary layer, commonly the water surface temperature is higher than the air temperature.…”